What's the difference between these two caps?

[ledtester]

They have similar specs, but one is massively larger than the other.

Why would you choose to use one versus the other?

[edpalmer42]

With two different pictures and no size measurements it's hard to compare them, but.....

The blue capacitor:
- Nippon Chemi-con is one of the best capacitor brands in the world.  They don't cut corners to make a smaller capacitor.
- Date code 0249 - 2002, week 49.  Technology has improved in the past 16 years so a current capacitor could be smaller.
- Temperature rating of 95C is unusual.  Normally it's either 85C or 105C.  Maybe just a change in ratings, but given the company's reputation, could be a slightly higher quality unit.  That might require a larger size.

The black capacitor:
More info is required.  Physical size, brand, temperature rating, date code all affect the size.  When everything is comparable, larger caps tend to have a longer life than smaller ones.  This may be reflected in the data sheets if you read them carefully.

As long as the unit survives past the warranty period, the bean counters will happily buy the cheapest crap they can and everyone else can go to hell.


Ed

[ledtester]

They are both Nippon Chemi-cons. Date code appears to be "0723" - 23rd week of 2007?

Some dimensions:

blue   - 50 mm diameter, 50 mm height
brown - 35 mm diameter, 45 mm height

The blue one has screw terminals, the brown one snap-in terminals.

[BravoV]

Why I read Nichicon , instead of Nippon ChemiCon ? They're different companies.

[MosherIV]

larger caps tend to have a longer life than smaller ones.  This may be reflected in the data sheets if you read them carefully. 

Agreed 

I am no expert in the field. An electronics engineer (I am asoftware engineer with a degree in Elec Electronic Engineering and hobbiest) explained to me that it is about Q factor which boils down to how well the cap handles ripple current. The better the Q the better it is at handling large ripple current.
Size probably helps, ie more surface area of plates is better than dielectric or gap seperation.
The bigger the cap, the more it costs.

All the stuff about low esr and cap going bad and buldging is sometimes due to cheap/wrong caps (unable to handle high ripple current).

[dzseki]

Why I read Nichicon , instead of Nippon ChemiCon ? They're different companies.

Because the same reason why LG phones and TVs aren't called Goldstar anymore (Marketing)

[BravoV]

Why I read Nichicon , instead of Nippon ChemiCon ? They're different companies.

Because the same reason why LG phones and TVs aren't called Goldstar anymore (Marketing)

Looks like you forgot to wear your glasses, look again ... 

[dzseki]

Why I read Nichicon , instead of Nippon ChemiCon ? They're different companies.

Because the same reason why LG phones and TVs aren't called Goldstar anymore (Marketing)

Looks like you forgot to wear your glasses, look again ... 

LOL, indeed, everyday I can learn something new...

[ledtester]

Why I read Nichicon , instead of Nippon ChemiCon ? They're different companies.

You're right! Reminds of the time I was in Hong Kong and though I was buying a name-brand calculator. On closer inspection it turned out to be a SHRAP.

[pigrew]

Another (possible) difference would be the material of the bung (the plug on the bottom, usually rubber).

I just replaced the capacitors in a piece of ~1990 HP equipment (proactively; in retrospect the capacitors are perfectly fine and probably should have been left).

The capacitors I took off have an epoxy end-cap over the rubber bung. This perhaps would have prevented them from leaking electrolyte (just my guess, I have no evidence of such). The datasheet for the removed capacitors suggested that solvent rinses should only be used with epoxy-coated bungs. Newer capacitors no longer have this limitation, the new rubber bungs can be solvent-washed. I don't know if the new capacitors will go bad before the old capacitors would have....

Choosing capacitors on Digikey always makes me wonder what the trade-off of diameter and height is. My guess is that taller capacitors would be more reliable due to less perimeter of the dielectric, and smaller bungs.

[Bassman59]

Why I read Nichicon , instead of Nippon ChemiCon ? They're different companies.

Because the same reason why LG phones and TVs aren't called Goldstar anymore (Marketing)

Lucky Goldstar.

[edpalmer42]

Why I read Nichicon , instead of Nippon ChemiCon ? They're different companies.

You're right! Reminds of the time I was in Hong Kong and though I was buying a name-brand calculator. On closer inspection it turned out to be a SHRAP.

Or was that SCRAP? 

Nichicon is another excellent brand, so both your samples are top quality capacitors.

The blue style is almost generic for use in open frame linear power supplies, regardless of brand.  Nippon Chemi-con might even have built a product line with that form factor just to tap into that market.

The black style has also become generic, first in switching supplies, but now for just about everything.  The LQ series has been replaced by the LS series which isn't listed as anything special (i.e. low ESR), so the size differences are likely due to manufacturing processes which are probably trade secrets, as well as popular form factors for different applications.

Ed